How did the discovery of DNA prove that Darwin’s theory of evolution was correct and how does it change the way we view evolution today and into the future?

How did the discovery of DNA prove that Darwin’s theory of evolution was correct and how does it change the way we view evolution today and into the future?

Darwin theory was that species will have changes in both physical and behavioural as time passes to make the organism more fit for its environment. Also the discovery of DNA proved his theory, by examining DNA it shows we all have a common ancestor. DNA also shows that when we are born we get some of our moms and some of our dads genes passed on to us, and sometimes there are mutations and often in animals the mutation is good or else the organism wont survive. By looking at DNA we can see certain mutations and places where DNA is different in species that were once the same. Darwin went to the Galapagos Islands and saw that the same species of finches looked different and though since they were on different Islands and they ate different things their beaks had to change in order for them to be able to eat. And those that didn’t change they would no longer be fit for the environment, they would die because they cant eat and their genes would not get passed on, this is called survival of the fittest.